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Pachelbel's Canon

Wednesday 15th January 2014 (10:30PM)

I've been exchanging emails with my buddy
Francis. We've been discussing classical
music. Much of the discussion has been about discerning the "clever stuff"
that may not be immediately obvious when listening to a piece of music.

It's possible to listen to any sort of music and simply enjoy the
sensation of the sounds. I do this quite often. However, there's also a hidden
world of clever, sneaky and fun tricks that composers and performers use to
bring about a performance. To use a mathematical analogy, it's the difference
between just appreciating the beautiful picture of the fractal (below)
compared to having the additional understanding of the simple and rather
beautiful mathematics that bring it into existence.

Put simply, sometimes it's fun to know exactly what's going on (in a
musical sense). Unfortunately, in the context of classical music, this usually
requires both historical and theoretical knowledge. So what do you do if you
don't have this knowledge? In the case of Francis, an obvious starting point
is to explore the classical pieces he already enjoys. When I asked him what
classical recordings he owned he replied,

I have and quite like Faure's Pavane, and Pachelbel's Canon.
Frustratingly though when I play them now they feel like cliches. This is
partly because I know them from childhood, so there's nothing new to me.
Partly because I don't know how to engage deeper beyond them.

So, I want to lift the curtain on Pachelbel's Canon and give you a sense of
some of the non-obvious "clever stuff" happening in the piece. I assume no
prior musical knowledge.

Rob Paravonian's humorous rant (above) centres around the fact that the
poor cellist (playing the lowest part) plays the same sequence of eight notes
28 times. This is a special type of ostinato (repeated pattern)
called a ground bass. As Rob demonstrates, the ground bass is a
technique that's (over) used in a lot of pop music. In the Baroque period (the
historical era during which Pachelbel was writing) composers used it as
an anchor within a piece so that the listener had some sort of expectation of
what was coming next. The clever bit is how the composer plays with our
expectations by setting contrasting, surprising and clever melodies over the
top of the ground bass.

In Pachelbel's case he starts by setting a very simple, regular step-wise
melody above the ground bass. As the piece continues each new repetition of
the ground bass has an increasingly complex setting above it until the melody
is moving quite quickly, is rhythmically more interesting (it's uneven) and
jumps around in pitch. Following this "climax" (yes, that is the correct term)
the melody gradually transforms into a slower moving, simpler and more
relaxed state that draws the piece to a close.

This is a sketch of the form of the piece at the macro (high)
level. But there are other levels of "resolution" that can be viewed under our
musical microscope.

For example, have you wondered why the piece is called "Pachelbel's Canon"
and not "Pachelbel's Ground Bass"? Well, a musical canon is a contrapuntal
technique where a single melody is played on top of itself with voices coming
in one after the other. You probably already know several canons and have
perhaps sung some at school: "Row, Row, Row Your Boat" and "Frere Jacques" are
well known examples. In any case, the way a canon is performed
is always the same: a first voice starts to sing or play the melody and, at
some regular period of time later, N number of voices gradually
join in one after the other and play the melody.

It is this "canonical" technique that Pachelbel uses. The piece is written
in four parts: the ground bass and three melody parts. However, each of the
melody parts plays exactly the same melody but offset by one
repetition of the ground bass. So, not only does the melody mysteriously fit
with the ground bass, but it fits with itself. Furthermore, Pachelbel has
organised things so that the macro form of the piece (the feeling of a
gradual build up to a climax followed by a relaxation to the end) emerges from
such micro level interactions between the different parts.

Cool huh..?

All of the features I describe above can be heard if you listen very
carefully. However, don't expect to hear them all at once! This is why so
much classical music deserves repeated listening because there's always
something new to spot! The following video is particularly useful because
the Musanim project have superimposed
a graphical version of the score that follows the performance. The ground
bass is represented by the blue blocks at the bottom of the screen and the
red, brown and yellow blocks represent each of the three melody parts.
Basically, the vertical axis is pitch (how high or low a note sounds) the
horizontal axis is time and colour represents the part being played (sometimes
the colours change if parts play the same note). If you watch and listen very
carefully you'll be able to spot the canonical relationship between each of
the melody parts.

Hang on a minute, if there are only four parts in the piece why are there
six performers..?

Obviously the cello is playing the ground bass. Each of the violinists is
playing one of the melody parts. The first violin is on the left, second in
the middle and the third to the right of the organ. Right of the organ? What's
an organ doing in there and what on earth is that funky guitar like thing on
the far right?

Well, these are the continuo group - a sort of Baroque-era rhythm section
(the instrument on the far right is, in fact, a Theorbo - a member of the lute
family of instruments). They follow the bass part (in this piece it's the
ground bass played by the cello) and improvise harmonic "filling" in much the
same way that a rhythm guitarist in a pop group or pianist in a jazz trio
do.

Now, watch the performance again, but this time I want you to concentrate
on what the performers are actually doing. Notice how they move a lot, swaying
from side to side and often change where they're facing. Since they're all
reading their parts they have to keep together in some way. Obviously they're
listening very carefully to each other but they're also aware of each other's
movements through the corner of their eyes. As a result they're able to get
a sense of what everyone else is doing and collectively work as an ensemble.
At certain points you'll see them glance, make eye contact with each other and
even smile. This is another means of non-verbal communication the players use
to keep their sense of ensemble (you see the third violinist do this about
halfway through the performance). Finally, at the end when they need to
coordinate the close of the performance everyone is looking at the first
violinist on the far left to get a sense of how the music is slowing down and
ultimately coming to a stop.

Each group works in a different way and watching an ensemble's group
dynamics is yet another aspect of classical music that allows for repeated
listening. It's fun to compare and contrast the different ways in which
performers react to and perform a piece of music